fix(templates): cross-validate against official Gitea mail templates

- Fix INK theme: replace .ActiveCodeLives with correct field, remove from non-auth contexts (8 files)
- Fix hardcoded button text: use locale key mail.view_it_on in ember, heritage, ink, mono, terminal, terra (30+ files)
- Add missing {{if .CanReply}}mail.reply{{end}} block to all 10 themes default.tmpl
- Add missing mail.release.note locale label to all 10 themes release.tmpl
- Add missing mail.team_invite.text_3 to ink and terra team_invite.tmpl
- Add missing blockquote CSS to aurora, ink, mono, neon, terra default.tmpl

Verified: all 110 templates compile successfully with Go build-preview.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

themes/bloom/mail/repo/issue/default.tmpl

@@ -65,7 +65,8 @@
           {{end}}
         {{else}}
           {{.Body}}
-        {{end -}}
+        {{end -}}{{if .CanReply}} {{.locale.Tr "mail.reply"}}{{end}}
+
         </p>
 
         {{- range .ReviewComments}}

themes/bloom/mail/repo/release.tmpl

@@ -31,6 +31,7 @@
         <h4 style="margin:20px 0 8px; font-size:17px; font-weight:600; color:#1e293b;">{{.locale.Tr "mail.release.title" .Release.Title}}</h4>
 
         {{if .Release.RenderedNote}}
+          {{.locale.Tr "mail.release.note"}}<br>
           <div style="margin:12px 0 16px; font-size:14px; line-height:1.6; color:#475569;">
             {{.Release.RenderedNote}}
           </div>